1. Field
This disclosure is directed to a thin layer having a composition gradient and a method for the production of the thin layer. More specifically, the thin layer is produced by a sol-gel process and has a composition gradient that enables the control of the surface energy of the thin layer, leaving no interfacial failure defects.
2. Description of the Related Art
With the recent remarkable development of electronic display devices and their related technologies, considerable research has been devoted to the development and application of electronic display devices with various characteristics. In this connection, one approach to impart particular characteristics to electronic display devices is associated with methods for the formation of thin layers. As display devices have been rendered lightweight and small, methods for the formation of thin layers and the characterization of the thin layers are gaining importance. Under these circumstances, research on the kind of characteristics available to impart to thin layers or how to reduce the formation of defects at the interfaces between thin layers and other materials is actively underway.
For example, flexible devices are required to have various characteristics such as non-fragility and flexibility. Organic materials are included in flexible devices to achieve flexibility of the flexible devices. However, typical electronic display devices, such as organic light emitting diodes (“OLEDs”) and liquid crystal displays (“LCDs”), include organic materials that are highly sensitive to oxygen or water vapor present in the air, which adversely affects the lifetime of the devices. Flexible devices also need improved characteristics in terms of moisture and gas barrier properties. Many methods have been developed for the protection of electronic display devices using metals and glass to prolong the lifetime of the devices. However, metals are generally disadvantageous in terms of transparency, and glass is not suitable for use in electronic display devices because of its fragility and poor flexibility. Thus, there is a need to develop flexible transparent barrier films or encapsulation thin layers suitable for use in the encapsulation of bendable, thin, and lightweight flexible OLEDs and other electronic devices.